A new imaging technology allows researchers to find the earliest signs of possible Alzheimer's disease in patients showing slight declines in memory.
Currently, doctors use memory tests to detect Alzheimer's disease because there is no definitive test for this disease. However, this new scan marks one of the first potential tools to diagnose Alzheimer's disease in a patient years before the symptoms are noticeable.
"The imaging technology may also allow us to test novel drug therapies and manage the disease progression over time possibly protecting the brain before damage occurs," said Dr. Gary Small, lead study author and professor at the Semel Institute for Neuroscience and Human Behavior at UCLA.
More than 4.5 million Americans have currently been diagnosed with Alzheimer's disease, but it is estimated that up to 30 million more have some early signs of the disease in the form of mild cognitive impairment.
It is believed that Alzheimer's disease occurs when abnormal proteins are deposited in the brain. At first, these deposits seem to cause mild memory problems, but as the proteins build up a person's cognitive ability can become more severely limited.
Small and colleagues developed a molecule called a "marker" that binds to these proteins in the brain so they can be detected by a positron emission tomography (PET) scan.
In a study of the scan, researchers looked at 83 volunteers between the ages of 49 and 84. Based on cognitive tests, 25 of the participants had Alzheimer's disease and 28 had some mild cognitive impairment. The results of the study were published in The New England Journal of Medicine.
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First, the participants were given an injection of the marker and then given the PET scan. The scan showed that more of the marker was found in the brains of those participants with the most advanced forms of Alzheimer's disease. But, even more, these markers were found in those patients with mild memory loss.
"We could see the definitive patterns started early in patients with mild cognitive impairment and advancing in those with Alzheimer's disease," said Dr. Jorge Barrio, study author from the David Geffen School of Medicine at UCLA.
Two years later, 12 of the participants were rescanned. Not surprisingly, those patients whose mental condition had grown worse showed a 5 to 11 percent increase in the amount of the marker that was found in the brain.
"The study suggests that we may now have a new diagnostic tool for detecting pre-Alzheimer's conditions to help us identify those at risk, perhaps years before symptoms become obvious," said Small. Then, treatment may be started earlier to try to slow down the devastating effects of this disease, he says.
